1. Field of the Invention
This invention relates to the field of internal combustion engines, and particularly to a device for assisting an engine assembler to torque the head bolts of the engine in the proper sequence.
2. Description of the Prior Art and Related Information
Internal combustion engines of the type with reciprocating pistons are generally constructed with a cylinder block and a separable cylinder head. The cylinder head is typically secured to the cylinder block by a plurality of bolts ("head bolts") threaded into the cylinder block. In many engines, studs are inserted into the cylinder block and the head is then secured by nuts threaded over the top of each stud.
When assembling the cylinder head to the cylinder block, either during initial assembly of the engine or following an overhaul procedure, it is critical that each of the head bolts or nuts, as the case may be, be tightened to a specified torque setting in the proper sequence. The torquing sequence is important for ensuring proper compression of the head gasket placed between the cylinder block and the cylinder head. It is also important to prevent warping of the cylinder head which may occur if the head bolts are torqued in the improper sequence.
When fitting a cylinder head to the cylinder block, the assembler will typically refer to a chart or diagram, usually in an engine assembly or repair manual, which illustrates the head bolt torquing sequence. Such a reference tool is frequently inconvenient as it may not be readily available at the time of assembly. Moreover, such a diagram is easily soiled during the assembly process, perhaps making it unsuitable for use at a later time.
Because of the inconvenience of traditional torquing sequence diagrams, assemblers are frequently tempted to rely on memory of the proper torquing sequence or to simply disregard the importance thereof. The consequences of doing so may result in premature engine failure.